CN110168161B

CN110168161B - Sizing agent-coated carbon fiber bundle, thermoplastic resin composition, molded body, method for producing sizing agent-coated carbon fiber bundle, and method for producing molded body

Info

Publication number: CN110168161B
Application number: CN201780082850.2A
Authority: CN
Inventors: 四方孝幸; 吉弘一贵; 野口知久; 市川智子
Original assignee: Toray Industries Inc
Current assignee: Toray Industries Inc
Priority date: 2017-02-24
Filing date: 2017-11-10
Publication date: 2020-06-23
Anticipated expiration: 2037-11-10
Also published as: RU2019129529A; US20190390022A1; WO2018154867A1; US10738171B2; TW201835241A; MX2019008543A; EP3546642A4; EP3546642B1; KR20190058676A; CN110168161A; EP3546642A1; KR102090924B1

Abstract

Provided is a sizing agent-coated carbon fiber bundle which exhibits good fiber-opening properties even in the case of exhibiting a high level of adhesion to a thermoplastic resin in the fiber-opening step of a sizing agent-coated carbon fiber. The carbon fiber bundle coated with the sizing agent contains at least a compound (a) containing an amino group or an amide group as a sizing agent component.

Description

Sizing agent-coated carbon fiber bundle, thermoplastic resin composition, molded body, method for producing sizing agent-coated carbon fiber bundle, and method for producing molded body

Technical Field

The present invention relates to a sizing agent-coated carbon fiber bundle exhibiting high adhesion to a thermoplastic resin and having a sizing agent applied thereto (which exhibits good fiber-opening properties in a fiber-opening step of a sizing agent-coated carbon fiber), a thermoplastic resin composition using the sizing agent-coated carbon fiber bundle, a molded body, a method for producing the sizing agent-coated carbon fiber bundle, and a method for producing the molded body (in the present invention, referred to as a "thermoplastic resin molded body" and simply referred to as a "molded body").

Background

Carbon fibers are lightweight and excellent in strength and elastic modulus, and therefore composite materials obtained by combining them with various matrix resins have been used in many fields such as aircraft members, spacecraft members, automobile members, ship members, civil engineering and construction materials, and sporting goods. A typical form of the composite material using carbon fibers is a molded article obtained by pressure molding (a molding method in which deaeration and shaping are performed under a pressure) a preform obtained by laminating prepregs. The prepreg is generally produced by the following method: the resin is impregnated into a carbon fiber base material obtained by arranging continuous carbon fibers in a single direction. Composite materials using discontinuous carbon fibers (chopped fibers, nets, etc.) that have excellent shape-following properties for complex shapes and can be molded in a short time have also been proposed, but prepregs have excellent practical properties as structural members in terms of mechanical properties such as specific strength and specific rigidity, and stability of properties.

In recent years, a molding material excellent in moldability, handling properties, and mechanical properties of a molded article to be obtained has been required for a carbon fiber composite material, and further high economical efficiency and productivity have been industrially required. In response to this demand, development of prepregs using a thermoplastic resin as a matrix resin has been advanced.

In order to exhibit the excellent properties of carbon fibers, it is important to improve the adhesion between the carbon fibers and the matrix resin. In order to improve the interfacial adhesion between the carbon fiber bundle and the matrix resin, the following method is generally performed: the carbon fiber bundle is subjected to oxidation treatment such as vapor phase oxidation or liquid phase oxidation to introduce functional groups containing oxygen to the surface of the carbon fiber. For example, patent document 1 proposes the following method: by subjecting the carbon fiber bundle to electrolytic treatment, the interlaminar shear strength, which is an index of interfacial adhesiveness, is improved.

When sufficient interfacial adhesion cannot be obtained only by surface modification of carbon fibers, additional slurry treatment is attempted. For example, patent document 2 proposes the following method: by applying polyethyleneimine as a sizing agent to carbon fiber bundles, the adhesion to a thermoplastic resin having a small number of functional groups is improved. In addition, patent document 3 adopts a method of applying polyethyleneimine as a sizing agent after processing a carbon fiber bundle into a net or the like at a high order. In addition, in patent document 4, a high molecular weight and high viscosity polyethyleneimine is used as a sizing agent in a carbon fiber bundle, thereby producing chopped carbon fibers that are not easily dispersed in an injection molding machine.

Patent documents 5 and 6 propose the following methods: by using an amine compound and a surfactant as a lubricant, it is possible to suppress the occurrence of fuzz particles in the production process of fibers.

As described above, in the field of composite materials using continuous and discontinuous carbon fibers, studies have been made to improve adhesion, and studies have been made to suppress fuzz particles and improve fiber opening properties by using a lubricant. On the other hand, when the above-described technique is applied to a prepreg using a thermoplastic resin as a matrix resin, there is no idea as follows: the carbon fiber bundles coated with the sizing agent have high fiber opening property and high adhesion property with the matrix resin, so that the impregnation property of the high-viscosity thermoplastic resin is improved, and the impregnation unevenness and the generation of voids are inhibited.

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. H04-361619

Patent document 2: japanese patent laid-open publication No. 2013-166924

Patent document 3: japanese laid-open patent publication No. 2006-089734

Patent document 4: japanese laid-open patent publication No. H03-065311

Patent document 5: japanese Kohyo publication 2002-528661

Patent document 6: japanese patent laid-open No. 2006 and 161018

Disclosure of Invention

Problems to be solved by the invention

The present invention has been made in view of the above circumstances, and an object thereof is to provide a carbon fiber bundle coated with a sizing agent, which exhibits good fiber-opening properties in a fiber-opening step of the carbon fiber bundle coated with the sizing agent even when exhibiting a high level of adhesion to a thermoplastic resin.

Means for solving the problems

According to the research of the inventor of the present application, it can be known that: when a compound having a strong interaction with the matrix resin and high adhesiveness, such as the compound (a), is used as the sizing agent, there are problems in that the fiber opening property of the carbon fiber bundle coated with the sizing agent is easily lowered, and impregnation unevenness and voids are easily generated when a prepreg is produced. In order to solve the above problems, it has been found that the interaction between carbon fibers can be highly controlled by strictly controlling the molecular weight and viscosity of the compound (a) and the amount of the sizing agent attached, and that high fiber-opening properties and high adhesion properties can be simultaneously achieved.

Further, it is known that when a smoothing component is added to a sizing agent as a general means for improving the fiber-opening property, the fiber-opening property is improved, but the adhesive property is lowered with a decrease in the ratio of the compound (a) as a high adhesive component, and it is difficult to achieve both the adhesive property and the fiber-opening property in a simple combination. In order to solve the problem, it has been found that a smoothing agent having a specific chemical structure is added by controlling the ratio of the compound (a) to form a gradient structure on the carbon fiber by the compound (a) and the compound (B), and that a high opening property and a high adhesion property of the carbon fiber bundle coated with the sizing agent are achieved.

When a sizing agent obtained by mixing a compound (a) containing an amino group or an amide group and a compound (B) as a smoothing component having a specific chemical structure is used, the following phenomenon is observed: the more polar compound (a) tends to be biased largely toward the carbon fiber side, while the less polar compound (B) tends to be biased toward the outermost layer of the sizing agent layer on the side opposite to the carbon fiber. As a result of the gradient structure of the sizing agent layer, the compound (a) strongly interacts with the carbon fibers in the vicinity of the carbon fibers, and the adhesiveness is improved. Further, the compound (B) as the smoothing component reduces the friction coefficient of the surface layer of the monofilaments in the carbon fiber bundle, and thereby improves the sliding between the monofilaments in contact during the opening process, and thus the opening property can be improved. As a result, the interfacial adhesiveness between the carbon fibers and the matrix resin can be improved, and the physical properties of the obtained carbon fiber-reinforced composite material can be improved.

In order to solve the above problems and achieve the object, a sizing agent-coated carbon fiber bundle of the present invention is a sizing agent-coated carbon fiber bundle in which a sizing agent containing a compound (a) containing an amino group or an amide group is coated on carbon fibers, and is characterized by satisfying the following (i) or (ii).

(i) The carbon fiber bundle coated with a sizing agent comprises 50 parts by mass or more of a compound (A) containing an amino group or an amide group and has a length of 10cm or more per 100 parts by mass of the total amount of the sizing agent, wherein the weight average molecular weight Mw of the compound (A) is 2500 or less, the viscosity of the compound (A) at 25 ℃ is 200 to 10000 mPas, and the amount X of the sizing agent attached represented by the following formula (a) is 0.03% by mass or more and less than 0.1% by mass.

X＝(W0-W1)/W0×100(％)······(a)

W0-total mass of carbon fiber and sizing agent

W1 mass of carbon fiber only

(ii) A sizing agent-coated carbon fiber bundle in which carbon fibers are coated with a sizing agent comprising 50 parts by mass or more of a total amount of a compound (A) containing an amino group or an amide group and a compound (B) represented by the following formula (I) and/or (II) per 100 parts by mass of the total sizing agent, wherein the mass WA of the compound (A) and the mass WB of the compound (B) satisfy the formula (III), and the difference between the SP values of the compound (A) and the compound (B) is 0.5 to 4.0 (J/cm)³)^0.5。

R₁-COO-(CH₂CH₂O)_n-CO-R₂… … formula (I)

R₃-COO-(CH₂CH₂O)_n-H … … formula (II)

(in the formula, R₁、R₂、R₃Represents a hydrocarbon group having 1 or more carbon atoms. )

0.1. ltoreq. WB/(WA + WB) <0.6 … … formula (III)

The thermoplastic resin composition of the present invention is characterized by containing the carbon fiber bundles coated with the sizing agent and the thermoplastic resin (C).

The molded article of the present invention is a prepreg or a UD (unidirectional) tape using the thermoplastic resin composition.

The method for producing a carbon fiber bundle coated with a sizing agent of the present invention is characterized by comprising a step of coating the carbon fibers with the sizing agent using an aqueous solvent.

The method for producing a molded article of the present invention includes the steps of: the thermoplastic resin composition is obtained by using the carbon fiber bundles coated with the sizing agent and the thermoplastic resin (C), and then the thermoplastic resin composition is heated to 300 ℃ or higher.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, a sizing agent-coated carbon fiber bundle having a high level of adhesion to a thermoplastic resin and exhibiting good fiber-opening properties in the fiber-opening step of the sizing agent-coated carbon fiber bundle can be obtained. As a result, the fiber content in the thermoplastic resin molded article can be made uniform, and the mechanical properties of the thermoplastic resin molded article including the carbon fiber bundle coated with the sizing agent are also improved.

Drawings

FIG. 1 is a diagram showing a method of measuring an average tearable distance.

Detailed Description

Hereinafter, embodiments for carrying out the present invention will be described.

The sizing agent of the present invention must contain a compound (a) containing at least either an amino group or an amide group.

The carbon fiber bundle coated with the sizing agent comprising the compound (a) containing an amino group or an amide group exhibits excellent adhesion to a thermoplastic resin. As a result, the mechanical properties of the thermoplastic resin molded article using the carbon fiber bundle coated with the sizing agent are improved. The mechanism is not clear, but is considered as follows: the amino group and the amide group have high polarity, and exhibit excellent adhesion by strong interaction such as hydrogen bond with a highly polar oxygen-containing structure such as a carboxyl group and a hydroxyl group in the surface of the carbon fiber bundle and the resin.

Examples of the compound (a) constituting the present invention include an aliphatic amine compound, an aromatic amine compound, an aliphatic amide compound, and an aromatic amide compound. Among them, aliphatic amine compounds are preferable from the viewpoint of exhibiting high adhesiveness. The reason why the aliphatic amine compound has high adhesiveness is considered to be that it has a very high polarity as compared with other compounds having an amino group and an amide group.

Specific examples of the aliphatic amine compound include aliphatic monoamines such as diethylenetriamine, triethylenetetramine, dicyandiamide, tetraethylenepentamine, dipropylenediamine, piperidine, N-dimethylpiperazine, triethylenediamine, polyamidoamine, octylamine, laurylamine, tetradecylamine, stearylamine, cocoalkylamine, tallowalkylamine, oleylamine, solidified tallowalkylamine, N-dimethyllaurylamine, and N, N-dimethyltetradecylamine; polyalkyleneimines such as polyethyleneimine, polypropyleneimine, polybutyleneimine, 1-dimethyl-2-methylethyleneimine, 1-dimethyl-2-propylethyleneimine, N-acetylpolyethyleneimine, N-propionylpolyethyleneimine, N-butyrylpolyethyleneimine, N-valerylpolyethyleneimine, N-hexanoylpolyethyleneimine and N-stearoylpolyethyleneimine, derivatives thereof, and mixtures thereof.

Among aliphatic amine compounds, compounds having 2 or more functional groups in 1 molecule are preferably used because the adhesiveness is easily improved. In particular, polyalkyleneimines are preferably used because the amount of functional groups contained in 1 molecule is easily increased and the adhesiveness is easily improved. As the reason why the adhesiveness of a compound containing 2 or more functional groups in 1 molecule is easily improved, it is considered that the polarity of the molecule is easily improved by increasing the amount of the functional groups.

Specific examples of the aromatic amine compound include 1, 2-phenylenediamine, 1, 3-phenylenediamine, 1, 4-phenylenediamine, benzidine, triaminophenol, triglycidyl-amino-cresol, 2,4, 6-triaminophenol, 1,2, 3-triaminopropane, 1,2, 3-triaminobenzene, 1,2, 4-triaminobenzene, 1,3, 5-triaminobenzene, derivatives thereof, and mixtures thereof.

Specific examples of the aliphatic amide compound include monoamides such as lauric acid amide, palmitic acid amide, stearic acid amide, behenic acid amide, oleic acid amide, erucic acid amide, ricinoleic acid amide, N-stearyl stearic acid amide, N-oleic acid amide, N-stearyl oleic acid amide, N-oleylstearic acid amide, N-stearyl erucic acid amide, N-oleylpalmitic acid amide, methylolstearic acid amide, and methylolbehenic acid amide; diamides such as methylene bis stearamide, ethylene bis capric acid amide, ethylene bis lauric acid amide, ethylene bis stearamide, ethylene bis isostearamide, ethylene bis hydroxystearic acid amide, ethylene bis behenic acid amide, hexamethylene bis stearamide, hexamethylene bis behenic acid amide, hexamethylene bis hydroxystearic acid amide, N ' -distearyladipamide, N ' -distearylsebacic acid amide, ethylene bis oleamide, hexamethylene bis oleamide, and N, N ' -dioleyladipamide; aliphatic polyamides such as nylon 6, nylon 66, nylon 11, nylon 12, nylon 46 and nylon 610, derivatives thereof, and mixtures thereof. In order to facilitate the hydration of the polyamide resin, a resin having a hydrophilic group such as a polyalkylene oxide chain or a tertiary amine component introduced into the molecule can be used. These aliphatic amides may be used alone or in combination of two or more.

Specific examples of the aromatic amide compound include aromatic amide amines such as aminobenzamide, aminobenzanilide, and aminobenzenesulfonamide; aromatic/aliphatic polyamides such as polyhexamethylene terephthalamide (nylon 6T) and nylon 6/6T copolymer, and derivatives thereof. These aromatic amides may be used alone or in combination of two or more.

In the sizing agent constituting the carbon fiber bundle coated with the sizing agent satisfying (i) according to the present invention, it is necessary to contain 50 parts by mass or more of the compound (a) with respect to 100 parts by mass of the total amount of the sizing agent (excluding the solvent). When the amount is 50 parts by mass or more, the adhesiveness is improved, and the physical properties of the thermoplastic resin molded product using the same are also improved. Preferably 60 parts by mass or more, and more preferably 80 parts by mass or more. As the component other than the compound (a), a nonionic surfactant and the like may be added as appropriate within a range not affecting the effect of the present invention.

In the carbon fiber bundle coated with a sizing agent satisfying (i) according to the present invention, the weight average molecular weight Mw of the compound (a) must be 2500 or less. The weight average molecular weight Mw is measured by a gel permeation chromatography (hereinafter abbreviated as GPC) method and obtained using pullulan as a standard substance. Since the higher Mw is the viscosity of the sizing agent, a large force is required to pull the carbon fibers bonded through the sizing agent apart from each other. When Mw is 2500 or less, viscosity, which is an index of ease of movement of the sizing agent, is reduced, and the force for restraining the carbon fibers from being weakened, thereby improving the fiber opening property of the carbon fiber bundle. The Mw is preferably 1500 or less, and more preferably 1000 or less. On the other hand, in view of decomposition, the larger the Mw, the more the volatilization and decomposition of the sizing agent at high temperature can be suppressed. The lower limit of Mw is preferably 500 or more, and more preferably 650 or more.

In the carbon fiber bundle coated with the sizing agent satisfying (i) of the present invention, the viscosity of the compound (a) at 25 ℃ must be 200 to 10000mPa · s. When the viscosity is 10000mPa · s or less, the force for restraining the carbon fibers from each other is weakened through the sizing agent, and the fiber opening property is improved. The viscosity is preferably 8000 mPas or less, more preferably 3000 mPas or less. The lower limit of the viscosity is not particularly limited, and the amount of the adhesive can be stably controlled in the process of applying the sizing agent to the carbon fiber bundle by setting the viscosity to 200mPa · s or more. In the present invention, the viscosity of the sizing agent at a temperature of 25 ℃ is measured at a frequency of 3.14rad/s using a viscoelasticity measuring instrument.

In the carbon fiber bundle coated with the sizing agent satisfying (i) according to the present invention, the sizing agent must be attached to the carbon fiber bundle at a ratio of 0.03 mass% or more and less than 0.1 mass%. By setting the amount of the sizing agent to be adhered to 0.03 mass% or more, the sizing agent uniformly adhered to the surface improves the abrasion resistance of the carbon fiber bundle, and can suppress the generation of fuzz during production and processing, thereby improving the quality such as smoothness of the carbon fiber sheet having good opening properties. The amount of adhesion is preferably 0.04% by mass or more, and more preferably 0.05% by mass or more. On the other hand, when the amount of the sizing agent attached is less than 0.1 mass%, the amount of the sizing agent present between the carbon fibers is reduced, and the restriction between the fibers can be weakened, so that the fibers can be easily opened by an external force, and the fiber bundle can be uniformly widened. The adhering amount is preferably less than 0.09 mass%, and more preferably less than 0.08 mass%.

In the sizing agent-coated carbon fiber bundle satisfying (i) according to the present invention, the length of each monofilament must be 10cm or more. The carbon fibers having a length of 10cm or more are considered to be substantially continuous, and the effect of improving the fiber opening property, which is a characteristic of the present invention, is more remarkably exhibited. Preferably 30cm or more, and more preferably 100cm or more.

The sizing agent constituting the carbon fiber bundle coated with the sizing agent satisfying (II) of the present invention must contain the compound (B) represented by the following formula (I) and/or (II).

R₁-COO-(CH₂CH₂O)_n-CO-R₂… … formula (I)

R₃-COO-(CH₂CH₂O)_n-H … … formula (II)

(in the formula, R₁、R₂、R₃Represents a hydrocarbon group having 1 or more carbon atoms. ).

The carbon fiber bundle coated with the sizing agent containing the compound (B) has a gradient structure with the compound (a) to reduce friction between filaments while maintaining adhesiveness, thereby improving smoothness between filaments in the opening step. As a result, the fiber opening property is improved. The carbon fiber bundle coated with the sizing agent facilitates opening of the fibers by external force, and the fiber bundle can be uniformly widened.

The sizing agent in the present invention preferably comprises a compound of formula (I) and/or formula (II). Since both terminal groups of the compound of formula (I) have hydrocarbon groups, the compound has high hydrophobicity and tends to concentrate on the surface layer of the sizing agent layer of the carbon fiber bundle coated with the sizing agent. Therefore, the fiber opening property is improved, and therefore, it is preferable. The compound of formula (II) has a hydrophilic group as a terminal group, and therefore is easily compatible with the compound (a) as a polar component, and forms a uniform gradient structure without phase separation in the sizing agent layer. Therefore, the fiber opening property is improved, which is preferable.

The compound (B) must be in the R of formula (I)₁、R₂R of (I), (II) and (II)₃The position (C) has a hydrocarbon group having 1 or more carbon atoms. The hydrocarbon group having high hydrophobicity is concentrated on the surface layer of the sizing agent on the carbon fiber, thereby reducing the friction coefficient of the surface. The number of carbon atoms is preferably 10 or more, and more preferably 15 or more. The number of carbon atoms is preferably 22 or less. When the content is 22 or less, the water solubility of the compound (B) is preferably improved.

In the sizing agent constituting the carbon fiber bundle coated with the sizing agent satisfying (ii) of the present invention, it is necessary to contain the compound (a) and the compound (B) in a total amount of 50 parts by mass or more with respect to 100 parts by mass of the total amount of the sizing agent (excluding the solvent). By containing 50 parts by mass or more, the effect of improving the adhesiveness by the compound (a) and the effect of improving the fiber opening property by the compound (B) can be exhibited. The physical properties of the thermoplastic resin composition using the same are also improved. The total amount of the compound (a) and the compound (B) is preferably 60 parts by mass or more, and more preferably 80 parts by mass or more.

In addition, in the sizing agent constituting the carbon fiber bundle coated with the sizing agent satisfying (ii) in the present invention, the mass WA of the compound (a) and the mass WB of the compound (B) must satisfy the formula (III). When the amount is 0.1 or more, the ratio of the compound (B) is preferably increased because the friction between fibers is reduced and the fiber opening property is improved. More preferably 0.2 or more. When the amount is less than 0.6, the ratio of the compound (A) increases, and the adhesiveness is improved, which is preferable. More preferably 0.5 or less, and still more preferably 0.3 or less.

0.1. ltoreq. WB/(WA + WB) <0.6 … … formula (III).

In order to achieve both adhesiveness and fiber-opening property, it is preferable that the mass WA of the compound (a) and the mass WB of the compound (B) satisfy formula (III), and that the compound (B) in the present invention is set to a range including 10 parts by mass or more with respect to 100 parts by mass (excluding solvent) of the total amount of the sizing agent, and the compound (a) is set to a range including 40 parts by mass or more with respect to 100 parts by mass (excluding solvent) of the total amount of the sizing agent. In addition, the content of the compound (B) in the present invention is more preferably 25 parts by mass or more per 100 parts by mass (excluding the solvent) of the total amount of the sizing agent, because the fiber opening property is further improved.

In the sizing agent of the present invention, the difference in SP value between the compound (A) and the compound (B) must be 0.5 to 4.0 (J/cm)³)^0.5. Here, the SP value is a generally known solubility parameter, which is an index of solubility and polarity. The SP value defined in the present invention is a value calculated from the molecular structure based on the method of Fedors described in Polym.Eng.Sci., 14(2), 147-. When the difference in SP values is 0.5 or more, the difference in polarity between the compound (A) and the compound (B) is large, and a gradient structure is formed. Preferably 1.0 (J/cm)³)^0.5The above is more preferably 2.0 (J/cm)³)^0.5The above. Is 4.0 (J/cm)³)^0.5In the following case, since the compatibility between the compound (a) and the compound (B) is increased, the domain formation of each component in the sizing agent is suppressed, the compound (a) and the compound (B) form a uniform gradient structure, and the adhesiveness and the fiber-opening property are improved, which is preferable. Preferably 3.5 (J/cm)³)^0.5More preferably 3.0 (J/cm) or less³)^0.5The following.

In the carbon fiber satisfying (i) according to the present invention, the average tearable distance of the carbon fiber is preferably 700mm or more. A long average tearable distance means that the carbon fibers are less entangled with each other, and a short average tearable distance means that the carbon fibers are more entangled with each other. When the distance is 700mm or more, the entanglement of the carbon fibers is small, and therefore, the probability of the carbon fibers being bonded to each other through the sizing agent is reduced, and therefore, the fiber bundle is easily widened uniformly by an external force in the opening step. The average tearable distance is more preferably 900mm or more. In the sizing agent-coated carbon fiber bundle of the present invention, as a means for making the average tearable distance within the above range, any method can be adopted, and this can be achieved by: in any step of a carbon fiber bundle or a process for producing a carbon fiber bundle, entanglement treatment by a fluid is suppressed, thereby reducing entanglement points between carbon fiber monofilaments.

The hydrophilic-lipophilic balance (HLB) of the compound (B) constituting the sizing agent-coated carbon fiber bundle satisfying (ii) in the present invention is preferably 10 or more. The HLB defined in the present invention is a value calculated from the molecular structure based on Griffin's method described in "New surfactant entry", page 128, (1992). In general, a sizing agent is applied to carbon fibers using a solution, and water is generally used as a solvent from the viewpoint of safety of the use environment. When the HLB of the compound (B) is 10 or more, the compound is uniformly dissolved in an aqueous solution, and thus the compound can be uniformly applied to the carbon fibers, and uneven adhesion of the sizing agent to the carbon fibers can be reduced. This is preferable because the fiber opening property is improved. More preferably 12 or more, and still more preferably 14 or more.

In the compound (B) constituting the sizing agent-coated carbon fiber bundle satisfying (II) in the present invention, n represented by formula (I) or (II) is preferably 12 or more. When n is 12 or more, the hydrophilicity of the compound (B) is improved, and when the sizing agent is applied to the carbon fibers using an aqueous solution, the uneven adhesion of the sizing agent to the carbon fibers can be reduced. n is more preferably 20 or more, and still more preferably 30 or more. Further, when the molecular weight is 100 or less, insolubilization in water due to the increase in molecular weight can be suppressed, and uneven adhesion can be reduced, which is preferable.

The melting point of the compound (B) constituting the sizing agent-coated carbon fiber bundle satisfying (ii) in the present invention is preferably 20 ℃ or higher. When the melting point is 20 ℃ or higher, it is preferable that the compound (B) is partially precipitated on the surface layer to exhibit a solid form when the compound (B) is used at room temperature (25 ℃), to reduce the friction between fibers, and to improve the fiber opening property. More preferably 40 ℃ or higher, and still more preferably 45 ℃ or higher. The upper limit is not particularly limited, and when the temperature is 50 ℃ or higher, the effect of improving the fiber opening property may be substantially saturated.

Specific examples of the compound (B) constituting the sizing agent-coated carbon fiber bundle satisfying (ii) in the present invention include polyethylene glycol fatty acid esters such as PEG monocaprylate, PEG monoethate, PEG monopelargonate, PEG monodecanoate, PEG monolaurate, PEG monotetradecanoate, PEG monopentadecanoate, PEG monopalmitate, PEG monolinoleate, PEG dilaurate, PEG monooleate, PEG dioleate, PEG dioctanoate, PEG diheptanoate, PEG dinonanoate, PEG didecanoate, PEG dilaurate, PEG ditetradecanoate, PEG dipentadecanoate, PEG dipalmitate, and PEG dilinoleate. These compounds (B) may be used singly or in combination of two or more. It should be noted that "PEG" is an abbreviation for "polyethylene glycol".

In addition, in the sizing agent constituting the carbon fiber bundle coated with the sizing agent satisfying (ii) in the present invention, the surface free energy of the compound (a) is preferably 45mJ/m²The above. The surface free energy is 45mJ/m²In the case described above, the compound (a) is preferably because it is likely to be localized on the surface of the carbon fiber, can form a gradient structure in the sizing agent, and can exhibit high adhesion. More preferably 50mJ/m²Above, it is more preferably 60mJ/m²The above.

Surface free energy refers to the energy that molecules on the surface of a solid or liquid have in addition to molecules inside a substance.

In the present invention, the surface free energy of the sizing agent of the compound (A) means the surface free energy at 25 ℃. The surface free energy can be obtained by a known method, for example, the following method.

First, the surface free energy of a thermoplastic resin flat plate was determined. As a calculation method, a liquid whose polar component and dispersion component of the surface free energy are known is dropped on a flat plate of a thermoplastic resin, and based on a contact angle measured from the shape of the produced liquid droplet, the square of the slope a is obtained from the above-mentioned fitting equation of Owens as the polar component (γ) of the surface free energy of the flat plate of a thermoplastic resin^p _s) And the square of the intercept b is determined as the polar component (gamma) of the surface free energy^d _s). The surface free energy (gamma) of the thermoplastic resin flat sheet is gamma^p _sAnd gamma^d _sAnd (4) summing.

Regarding the fitting formula of Owens, the surface free energy γ of the liquid is expressed_LSurface free energy polar component gamma^p _LSurface free energy dispersion component gamma^d _LAnd the contact angle θ obtained by the measurement is represented by formulae (IV) to (VI) and is plotted at X, Y. The surface energy of the liquid is calculated from the slope and intercept of the obtained fitting equation by creating a graph using two or more liquids whose polar components and dispersion components of the surface free energy are known, and fitting the obtained graph with a straight line by the least square method.

Y＝a·X+b……(IV)

X＝(γ^p _L)^0.5/(γ^d _L)^0.5……(V)

Y＝(1+cosθ)·(γ_L)/2(γ^d _L)^0.5……(VI)。

The surface free energy of the compound (A) can be determined by dropping a sizing agent on a flat thermoplastic resin plate whose surface free energy has been calculated by the above-mentioned method, and measuring γ of the above-mentioned formulae (IV) to (VI) from the contact angle obtained from the shape of the resulting liquid droplet^p _L、γ^d _LAnd then calculated.

In addition, in the sizing agent constituting the carbon fiber bundle coated with the sizing agent satisfying (ii) in the present invention, it is preferable that the sizing agent substantially does not contain a compound having an epoxy group. Here, the term "substantially not containing a compound" means that: such compounds are completely absent; or 1 part by mass or less based on the total amount of the sizing agent even if the sizing agent is present in the form of an additive. The highly reactive epoxy group reacts with the amino group at the terminal of the amine compound or amide compound to form a strong crosslinked structure. Therefore, by making the sizing agent substantially free of a compound having an epoxy group, the formation of a crosslinked structure between carbon fiber monofilaments is suppressed, and the fiber opening property is improved.

The carbon fiber bundle coated with a sizing agent satisfying (ii) according to the present invention preferably has an inter-fiber friction coefficient of 0.30 or less. When the amount is 0.30 or less, the friction between the filaments in the carbon fiber bundle is reduced, and thus the fiber opening property is improved. More preferably 0.25 or less.

The coefficient of friction between fibers can be controlled by the roughness of the carbon fiber surface, the kind and amount of the smoothing component contained in the sizing agent, and the amount of adhesion of the carbon fiber bundle coated with the sizing agent.

The coefficient of friction between fibers can be determined by the following procedure. The carbon fiber bundle wound around a fixed and non-rotating bobbin so as to have a uniform thickness is wound so that the same carbon fiber bundle as the roll is wound so that the contact angle is 3 pi (rad) and the carbon fiber bundle does not overlap on the circumference. The tension can be obtained by applying a weight to one end of the wound carbon fiber bundle and pulling the opposite end at a constant speed, based on the tension at the time when the wound carbon fiber bundle starts to move.

In the carbon fiber bundle coated with the sizing agent satisfying (ii) according to the present invention, the sizing agent is preferably attached in a proportion of 0.01 parts by mass or more and 1.0 part by mass or less with respect to 100 parts by mass of the total amount of the carbon fiber bundle coated with the sizing agent. By setting the amount of the sizing agent to be adhered to 0.01 part by mass or more, the sizing agent uniformly adhered to the surface improves the abrasion resistance of the carbon fiber bundle, suppresses generation of fuzz during production and processing, and can improve the quality such as smoothness of the carbon fiber sheet having good opening properties. The adhering amount is preferably 0.3 parts by mass or more. On the other hand, by setting the amount of the sizing agent to be attached to 1.0 part by mass or less, the amount of the sizing agent present between the carbon fibers is reduced, the restriction between the fibers can be weakened, the opening of the fibers by an external force becomes easy, and the fiber bundle can be uniformly widened. The adhering amount is preferably 0.7 parts by mass or less, and more preferably 0.5 parts by mass or less.

The carbon fiber bundle used in the present invention is not particularly limited, and polyacrylonitrile-based carbon fibers are preferably used from the viewpoint of mechanical properties. The polyacrylonitrile-based carbon fiber bundle used in the present invention can be obtained by: a carbon fiber precursor fiber formed from a polyacrylonitrile-based polymer is subjected to a flame-resistant treatment in an oxidizing atmosphere at a maximum temperature of 200 to 300 ℃, then subjected to a pre-carbonization treatment in an inactive atmosphere at a maximum temperature of 500 to 1200 ℃, and then subjected to a carbonization treatment in an inactive atmosphere at a maximum temperature of 1200 to 2000 ℃.

In the present invention, in order to improve the adhesion between the carbon fiber bundle and the thermoplastic resin, it is preferable to introduce an oxygen-containing functional group into the surface of the carbon fiber bundle by subjecting the carbon fiber bundle to an oxidation treatment. As the oxidation treatment method, gas phase oxidation, liquid phase oxidation and liquid phase electrolytic oxidation can be used, and from the viewpoint of high productivity and uniform treatment, liquid phase electrolytic oxidation is preferably used.

In the present invention, examples of the electrolyte solution used for the liquid-phase electrolytic oxidation include an acidic electrolyte solution and an alkaline electrolyte solution. Examples of the acidic electrolyte include inorganic acids such as sulfuric acid, nitric acid, hydrochloric acid, phosphoric acid, boric acid, and carbonic acid, organic acids such as acetic acid, butyric acid, oxalic acid, acrylic acid, and maleic acid, and salts such as ammonium sulfate and ammonium bisulfate. Among them, sulfuric acid and nitric acid showing strong acidity are preferably used. Specific examples of the alkaline electrolyte include aqueous solutions of hydroxides such as sodium hydroxide, potassium hydroxide, magnesium hydroxide, calcium hydroxide, and barium hydroxide, aqueous solutions of carbonates such as sodium carbonate, potassium carbonate, magnesium carbonate, calcium carbonate, barium carbonate, and ammonium carbonate, aqueous solutions of bicarbonates such as sodium bicarbonate, potassium bicarbonate, magnesium bicarbonate, calcium bicarbonate, barium bicarbonate, and ammonium bicarbonate, and aqueous solutions of ammonia, tetraalkylammonium hydroxide, and hydrazine.

In the present invention, the amount of the oxygen-containing functional group introduced into the carbon fiber bundle is preferably in the range of 0.14 to 0.30 in terms of the surface oxygen concentration (O/C), which is the ratio of the number of atoms of oxygen (O) to carbon (C) on the fiber surface as measured by X-ray photoelectron spectroscopy. When the O/C ratio is 0.14 or more, the carboxyl groups and hydroxyl groups on the surface of the carbon fibers increase, the interaction with the sizing agent becomes strong, and the adhesiveness is improved. The O/C ratio is preferably 0.16 or more, more preferably 0.18 or more. On the other hand, the smaller the O/C, the better, the O/C is preferably 0.30 or less, from the viewpoint of the decrease in strength of the carbon fiber itself due to oxidation. Preferably 0.25 or less, and more preferably 0.20 or less.

The O/C of the carbon fiber bundle can be determined by X-ray photoelectron spectroscopy according to the following procedure. First, a carbon fiber bundle from which dirt and the like adhered to the surface of the carbon fiber bundle had been removed by a solvent was cut to 20mm, spread and arranged on a copper sample support table, and then used AlK_α1、2As an X-ray source, the sample processing chamber was held at 1 × 10^-8And (5) Torr. As a correction value of the peak generated with the charging at the time of measurement, the bond energy value of the main peak (peak top) of C1s was associated with 284.6 eV. C_1sThe peak area is determined by drawing a linear base line in the range of 282 to 296 eV. O is_1sThe peak area is determined by drawing a linear base line in the range of 528 to 540 eV. Here, the surface oxygen concentration is determined from the above-mentioned peak area of O1s and C_1sThe ratio of the peak areas and the correction value of the sensitivity inherent to the use device were calculated as the atomic ratio.

Next, a method for producing a carbon fiber bundle coated with a sizing agent according to the present invention will be described.

First, means for applying (applying) the sizing agent to the carbon fiber bundle in the present invention will be described.

In the present invention, the sizing agent is preferably used in the form of a uniform solution by being diluted with a solvent. Examples of such a solvent include water, methanol, ethanol, 2-propanol, acetone, methyl ethyl ketone, dimethylformamide, and dimethylacetamide, and among these, water is preferably used because of its advantages in terms of ease of handling and safety.

Examples of the coating means include a method of immersing the carbon fiber bundle in a sizing agent solution via a roller, a method of bringing the carbon fiber bundle into contact with a roller to which the sizing agent solution is attached, a method of spraying the sizing agent solution onto the carbon fiber bundle, and the like. The means for applying the sizing agent may be either a batch type or a continuous type, and a continuous type having good productivity and capable of reducing variation is preferably used. In addition, when applying the sizing agent, it is also a preferable mode to apply vibration to the carbon fiber bundle with ultrasonic waves.

The concentration of the sizing agent solution used in the method of immersing the carbon fiber bundle in the sizing agent solution via the roller is preferably 1 mass% or less. When the amount is 1 mass% or less, the amount of the solid component to be adhered is preferably about 0.5 mass parts or less based on 100 mass parts of the carbon fiber bundle coated with the sizing agent, and the carbon fiber bundle coated with the sizing agent having excellent fiber opening property can be obtained. Further, the concentration of the sizing agent solution is more preferably 0.4 mass% or less.

When the amount is 0.4% by mass or less, the amount of the solid component adhering is preferably about 0.1 parts by mass or less based on 100 parts by mass of the carbon fiber bundle coated with the sizing agent, and the carbon fiber bundle coated with the sizing agent having more excellent fiber opening property can be obtained.

In the present invention, it is preferable that the carbon fiber bundle coated with the sizing agent is obtained by a contact drying means (for example, by contacting the carbon fiber bundle with a heated roll) after the sizing agent solution is applied. The carbon fiber bundle introduced into the heated roller is pressed against the heated roller by tension and is dried rapidly, and therefore, the flattened form of the carbon fiber bundle widened by the heated roller is easily fixed by the sizing agent. Since the contact area between single fibers of the carbon fiber bundle in a flat form is small, the fiber opening property is easily improved.

In the present invention, after passing the heated roller as the preliminary drying step, a heat treatment may be further applied as the 2 nd drying step. In the heat treatment in the 2 nd drying step, any heating method of a contact method and a non-contact method may be employed. By performing this heat treatment, the diluent solvent remaining in the sizing agent is further removed, and the viscosity of the sizing agent can be stabilized, so that the fiber opening property can be stably improved. The heat treatment conditions are preferably in the temperature range of 20 to 250 ℃. When the temperature is 20 ℃ or higher, the residual diluent solvent can be easily removed efficiently, and the fiber-opening property can be easily improved. On the other hand, when the upper limit of the heat treatment temperature is 250 ℃ or lower, thermal deterioration of the sizing agent component and crosslinking/thickening by self-polymerization can be suppressed, and the fiber opening property can be easily improved. Preferably 165 ℃ or lower, and more preferably 135 ℃ or lower.

When a nonionic surfactant, particularly the compound (B), is added as a smoothing component as a component other than the compound (a) within a range not affecting the effect of the present invention, crosslinking and thickening due to self-polymerization of the sizing agent can be suppressed, and the fiber opening property can be easily improved, so the temperature range of the heat treatment conditions is preferably 230 ℃ or less, more preferably 215 ℃ or less.

The heat treatment may be performed by microwave irradiation and/or infrared irradiation.

In the present invention, the carbon fiber bundle coated with the sizing agent is preferably composited with the thermoplastic resin (C) to form a thermoplastic resin composition.

The thermoplastic resin (C) in the present invention is preferably at least one thermoplastic resin selected from the group consisting of polyketone resins, polyetherketone resins, polyethernitrile resins, polyimide resins, polyamideimide resins, polyetherimide resins, polysulfone resins, polyethersulfone resins, polyarylene sulfide resins, polyetheretherketone resins, polyphenylene ether resins, polyoxymethylene resins, polyamide resins, polyester resins, polycarbonate resins, fluorine resins, styrene resins, and polyolefin resins.

In the present invention, when the glass transition temperature of the thermoplastic resin (C) is less than 200 ℃, the molding temperature can be reduced, and the load on the equipment is reduced, which is preferable. When the glass transition temperature of the thermoplastic resin (C) is 200 ℃ or higher, the thermoplastic resin (C) is preferable because it is excellent in heat resistance and mechanical properties and the properties of a molded article using the thermoplastic resin composition are improved. The thermoplastic resin having a temperature of 200 ℃ or higher has a higher viscosity at the same temperature than other thermoplastic resins, and therefore, the impregnation property during molding is lowered, and there are problems that impregnation is not uniform and voids are likely to be generated. The above resin is preferable because the mechanical properties of the resin such as flexural strength and tensile strength are high and the strength of a molded article using the thermoplastic resin composition is improved. As the thermoplastic resin, a thermoplastic resin containing a plurality of these resins can be used within a range not impairing the object of the present invention.

The thermoplastic resin composition of the present invention can be suitably used in the form of a molding material such as a prepreg or a UD tape.

Next, a method for producing a molded article using the thermoplastic resin composition of the present invention will be described. The method for producing a molded article of the present invention preferably includes a step of heating to 300 ℃ or higher when the thermoplastic resin composition is obtained using the carbon fiber bundles coated with the sizing agent and the thermoplastic resin (C). When the thermoplastic resin composition is molded by heating to 300 ℃ or higher in the molding step, the thermoplastic resin sufficiently penetrates into the fiber bundle, and the impregnation property is improved, whereby the physical properties of the thermoplastic resin composition are also improved. In general, when the heating temperature in the molding step is increased, there is a possibility that a decomposition product of the sizing agent is generated to adversely affect the molded product, but the carbon fiber bundle coated with the sizing agent of the present invention has a small amount of the sizing agent attached, and thus such an adverse effect can be reduced.

Specific examples of the molded article obtained by molding the thermoplastic resin composition of the present invention include a molding material (for example, particles, a stampable sheet, a UD tape, a prepreg, and the like, which are exemplified below) used for producing a molded article, in addition to a molded article as a final product.

Specific examples of the molded article of the present invention include, in addition to molding materials such as pellets, stampable sheets, UD tapes and prepregs, interior members such as housings and brackets of electric and electronic devices such as computers, displays, OA devices, cellular phones, portable information terminals, facsimiles, optical disks, portable MDs, portable radio recorders, PDAs (portable information terminals such as electronic notebooks), video cameras, digital still cameras, optical devices, audio devices, air conditioners, lighting devices, entertainment products, toy products, and other household electric products, building material applications such as housings, structural members and plates thereof, motor members, alternator terminals, alternator connectors, IC regulators, potentiometer bases for dimmers, suspension system members, various valves such as exhaust valves, fuel-related pipes, exhaust pipes, intake pipes, and exhaust pipes, Intake pipe nozzle, intake manifold, various arms, various frames, various hinge flaps, various bearings, fuel pump, gasoline tank, CNG tank, engine cooling water pipe joint, carburetor body, carburetor gasket, exhaust gas sensor, cooling water sensor, oil temperature sensor, brake gasket wear sensor, throttle position sensor, crank position sensor, air flow meter, brake gasket wear sensor, air conditioner thermostat base, heating device hot air flow control valve, radiator motor brush holder, water pump impeller, turbine blade, wiper motor-related component, distributor, starter switch, starter relay, transmission wiring, window washer nozzle, air conditioner panel switch base plate, fuel-related solenoid valve coil, melter connector, battery bracket, AT bracket, headlamp support frame, pedal case, motor cover, and motor cover, The automobile and two-wheel vehicle comprises automobile and two-wheel vehicle related components such as a steering wheel, a vehicle door anti-collision beam, a protective cover, a chassis, a vehicle frame, handrails, a horn terminal, a stepping motor rotor, a lamp holder, a vehicle lamp reflector, a lamp shade, a brake piston, a noise baffle, a radiator support, a spare tire housing, a seat shell, an electromagnetic coil bobbin, an engine lubricating oil filter, an ignition device shell, a lower cover plate, an anti-friction plate, a column decoration, a driving shaft, a roller, a mudguard, an instrument panel, a bumper beam, a hood, a pneumatic component, a platform, a hood vent hole, a top plate, an instrument panel, a; aircraft-related components and members such as members and outer panels, landing gear panels, wingtips winglets, spoilers, flaps, rudders, elevators, fairings, ribs, and the like; and outer plates, blades of windmills, and the like. In particular, the present invention is preferably used for aircraft members, blades of wind turbines, automobile outer panels, housings and brackets of electronic devices, chassis, and the like.

Examples

The present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

< method for measuring weight average molecular weight Mw >

The weight average molecular weight of the sizing agent can be measured by a known method using pullulan as a standard substance using GPC. As the measurement conditions of GPC, the following conditions are adopted in the present invention.

A measuring device: shimadzu manufacturing System

The column used: shodex Asahipac manufactured by Shorey electrician

GF-710HQ+GF-510HQ+GF-310HQ

Eluent: 0.2 mol% aqueous monoethanolamine solution

(adjustment to pH5.1 by addition of acetic acid)

Standard substance: pullulan (manufactured by Sigma-Aldrich Co., Ltd.)

A detector: differential refractometer (Shimadzu corporation).

< method for measuring viscosity of sizing agent >

The viscosity of the sizing agent was measured using a viscoelasticity measuring instrument. As the measurement conditions, a parallel plate having a diameter of 40mm was used, and the measurement was carried out at a frequency of 3.14rad/s at 25 ℃ with the span (span) being 1 mm.

< method for measuring amount of sizing agent adhered >

2.0. + -. 0.5g of the carbon fiber bundle coated with the sizing agent was weighed as (W1) (4 th position after reading to decimal point) and then heated in a nitrogen stream of 50 ml/min in an electric furnace (capacity 120 cm) set at a temperature of 450 ℃³) Left for 15 minutes to allow the sizing agent to be completely thermally decomposed. Subsequently, the carbon fiber bundle was transferred to a vessel under a flow of 20 liters/min dry nitrogen, and the amount of the sizing agent attached was determined from W1 to W2, wherein the carbon fiber bundle was weighed and recorded as (W2) (4 th position after decimal point reading) after cooling for 15 minutes. The amount of the sizing agent attached was converted into 100 parts by mass of the carbon fiber bundle, and the obtained value (rounding off the 3 rd position after decimal point) was taken as the amount of the sizing agent attached (parts by mass). The amount of the sizing agent adhered was determined as an average value of 2 measurements.

< method for measuring average tearable distance of carbon fiber bundle coated with sizing agent >

The carbon fiber bundle was cut to 1160mm in length, and one end thereof was fixed to a horizontal table by an adhesive tape so as not to move (this point is referred to as a fixing point a). Next, the unfixed end of the fiber bundle was divided into 2 parts by a finger, and one of the parts was fixed to a table in a tensioned state by an adhesive tape so as not to move (this point is referred to as a fixing point B). Then, the other of the two divided parts was moved along the table with the fixed point a as a fulcrum so as not to loosen, was made stationary at a position at a linear distance of 500mm from the fixed point B, and was fixed to the table with an adhesive tape so as not to move (this point is referred to as a fixed point C). The region surrounded by the fixed point A, B, C was visually observed, the interlace point farthest from the fixed point a was found, and the distance projected on the straight line connecting the fixed point a and the fixed point B was read with a ruler having a minimum scale of 1mm and used as the tearable distance. The above procedure was repeated for 30 measurements, and the arithmetic mean was taken as the average tearable distance. The method for measuring the tearable distance is shown in fig. 1. In the present measurement method, the interlacing point farthest from the fixed point a is a point where 3 or more single fibers that are farthest from the fixed point a in a straight line and have no slack are interlaced.

The average tear distance was evaluated at 3 levels according to the following criteria, and a and B were defined as passed.

A: the average tearing distance is more than 900mm

B: the average tearing distance is 700mm or more and less than 900mm

C: the average tear distance is less than 700 mm.

< method for measuring Friction coefficient between fibers >

The thickness is 5 to 10mm and the roll density is 0.9 to 1.4g/cm in a manner of uniform thickness³The same carbon fiber bundle as the roll is wound so that the contact angle becomes 3 pi (rad) and the carbon fiber bundle does not overlap on the circumference. A weight (T1) was applied to one end of the wound carbon fiber bundle, the opposite end was pulled at a speed of 1m/min by a spring balance, and the tension at the start of the movement of the wound carbon fiber bundle was set to T2, and the coefficient of friction between fibers was obtained according to the following equation.

Coefficient of friction between fibers ln (T2/T1)/theta

T2: tension when carbon fiber starts moving (indicated value of spring balance)

T1: weight (0.19 g/tex)

θ: total contact angle of roll with wound fiber (═ 3 π rad)

Two measurements were made, and the average value was taken as the coefficient of friction between fibers. The bobbin used for the measurement was placed under the temperature and humidity conditions of the measurement atmosphere (measurement conditions: 23. + -. 3 ℃ C./60. + -. 5%) before the measurement was carried out for 2 hours or more.

< method for measuring interfacial shear Strength (IFSS) >

The filaments were pulled out from the carbon fiber bundle coated with the sizing agent, sandwiched by the laminated resin films from the top and bottom, and a molded plate in which the carbon fiber filaments were embedded was obtained by a hot press. A dumbbell-shaped test piece for IFSS measurement was punched out of the molded plate.

The tensile strength σ of the bundle and the diameter d of the carbon fiber filament were measured by calculating the critical fiber length lc. from the average broken fiber length la and using a formula of lc (μm) ═ 4/3) × la (μm), and the interfacial shear strength (IFSS) which is an index of the adhesion strength between the carbon fiber and the resin interface was calculated by the following formula, and in examples, the average value of the measurement number n is 5 was used as a test result.

IFSS(MPa)＝σ(MPa)×d(μm)/(2×lc)(μm)。

In the present invention, preferred ranges of IFSS are as follows.

Thermoplastic resin

Polyether imide 40MPa or more

Polyphenylene sulfide of 24MPa or more

Polypropylene of 15MPa or more.

< method for measuring opening Property (opening holding ratio) >

Three sizing agent-coated carbon fiber bundles cut to a length of 380mm were prepared, and these three were equally arranged on thick paper (width 300mm, length 430mm) set on a horizontal table. Next, the upper portions 1/3 at both ends of the fiber bundle extending in the width direction were fixed with an adhesive tape. Then, the lower portions 1/3 at both ends of the fiber bundle extending in the width direction were gripped with both hands, and the fiber bundle was stretched downward by 80mm in parallel for 3 seconds, and the hands were released. The fiber width of the fiber bundle having good opening properties was 80mm, but the fiber width of the fiber bundle having poor opening properties was shortened. This operation was repeated for three fibers, and then the fiber width of each fiber bundle was measured to obtain an average value. Finally, the average value of the fiber width was divided by 80mm, thereby calculating the opening retention.

The opening retention was evaluated in three stages according to the following criteria, and a and B were defined as passed.

A: a fiber opening retention of 0.95 or more

B: the fiber opening retention rate is more than 0.90 and less than 0.95

C: the fiber opening retention ratio is less than 0.90.

< method for measuring fiber opening Property (non-opened portion) >

A bobbin wound with the carbon fiber bundle coated with the sizing agent was mounted on a bobbin holder in a horizontal manner to the ground, and the carbon fiber bundle coated with the sizing agent was pulled out from the bobbin by 300 mm. Then, the end of the drawn fiber was fixed with an adhesive tape. Then, blowing wind with a wind speed of 5-10 m/s to the carbon fiber bundle coated with the sizing agent in a state that the fiber bundle is loosened by 10-20 mm, and opening the fiber bundle. The number of portions where the monofilaments are bundled with adjacent monofilaments (non-opened portions) by the sizing agent was evaluated. At this time, the non-opened portion was evaluated in four stages based on the results of the above-described opening property (opening retention ratio) by using a portion having a width of 0.5mm or more as an evaluation target according to the following criteria, and A, B and C were regarded as passed.

A: number of non-opened portions: 0 pieces and a fiber opening retention of 0.95 or more

B: number of non-opened portions: 1 to 2 and a fiber opening retention ratio of 0.95 or more

C: number of non-opened portions: 1 to 2 and a fiber opening retention ratio of 0.90 or more and less than 0.95

D: number of non-opened portions: 3 or more, or the opening retention is less than 0.90.

< method for measuring opening Property (opening Width) >

The sizing agent-coated carbon fiber bundle having a length D1 in the width direction of the fiber bundle of 16cm was loosened by 1cm, and the sizing agent-coated carbon fiber bundle fixed to 2 cylindrical rods was blown with air at a wind speed of 5 to 30m/s for 30 seconds while being kept horizontal, and the fiber was opened, and the fiber width D2 was measured to calculate the opening width (D2/D1). This test was performed three times, and the average value was defined as the opening width. In the present invention, the preferable range of the opening width is 3.2 or more.

< measurement of glass transition temperature of thermoplastic resin >

The glass transition temperature of the thermoplastic resin was measured using Differential Scanning Calorimetry (DSC). The measurement was performed at a temperature rising rate of 40 ℃/min using an aluminum sample plate.

The materials and components used in the examples and comparative examples are as follows.

(A) Composition (I)

A-1: polyethylene imine

(Mw 1300, viscosity 6800mPa s, gamma 61 mJ/m)²)

(Lupasol (registered trademark) G20Waterfree, manufactured by BASF JAPAN, Ltd.)

A-2: polyethylene imine

(Mw 800, viscosity 1600 mPas, gamma 62 mJ/m)²)

(Lupasol (registered trademark) "FG manufactured by BASF JAPAN)

A-3: polyethylene imine

(Mw 2000, viscosity: 12030 mPas)

(Lupasol (registered trademark) "PR 8515 manufactured by BASF JAPAN corporation)

A-4: fatty acid amides

(Mw＝283.5，γ＝48mJ/m²)

(Amido (registered trademark) "AP-1 manufactured by Nippon chemical Co., Ltd.).

(B) Composition (I)

B-1: PEG distearate

(formula (I), n is 90, R₁、R₂＝17，HLB＝17.0)

(available from Sanyo chemical industry Co., Ltd. "IONET (registered trademark)" DS4000)

B-2: PEG monostearate

(formula (II), n is 22, R₃＝17，HLB＝15.7)

(available from Sanyo chemical industry Co., Ltd. "IONET (registered trademark)" MS1000)

B-3: PEG monooleate

(formula (II), n ═ 13, R₃＝17，HLB＝13.7)

(available from Sanyo chemical industry Co., Ltd. "IONET (registered trademark)" MO600)

B-4: PEG dioleate

(formula (I), n is 13, R₁、R₂＝17，HLB＝10.4)

(DO 600 "IONET (registered trademark)" manufactured by Sanyo chemical industry Co., Ltd.)

B-5: PEG distearate

(formula (I), n is 9, R₁、R₂＝17，HLB＝8.5)

(available from Sanyo chemical industry Co., Ltd. "IONET (registered trademark)") DS400)

B-6: PEG dioleate

(formula (I), n is 9, R₁、R₂＝17，HLB＝8.4)

(the product of Sanyo chemical industry Co., Ltd. "IONET (registered trademark)" DO 400).

(C) The components: thermoplastic resin

C-1: polyether imide

(glass transition temperature 217 ℃ C.)

(type E of Superior manufactured by Mitsubishi resin Co., Ltd.)

C-2: polyphenylene sulfide

(glass transition temperature 89 ℃ C.)

(Durafide (registered trademark) "PPS W-540 manufactured by Polyplastics Co., Ltd.)

C-3: polypropylene

(glass transition temperature-2 ℃ C.)

(Polypropylene J106G manufactured by Prime Polymer Co., Ltd.).

Other ingredients

Polyglycerol polyglycidyl ether

(Denacol (registered trademark) "Ex-314 manufactured by Nagasechemtex Co., Ltd.)

PEG

(Sanyo chemical industry (manufactured by Kabushiki Kaisha) PEG600)

In examples and comparative examples, the PEG was calculated as a component of the compound (B).

(example 1)

The present embodiment includes the following steps 1 to 4.

Step 1: process for producing carbon fiber bundle as raw material

The acrylonitrile copolymer was spun and fired to obtain a carbon fiber bundle having a total number of filaments of 12,000, a total fineness of 800tex, a strand tensile strength of 5.1GPa, and a strand tensile elastic modulus of 240 GPa. Next, the carbon fiber bundle was subjected to electrolytic surface treatment using an ammonium bicarbonate aqueous solution as an electrolyte solution and an electric quantity of 80 coulombs per 1g of the carbon fiber bundle. The carbon fiber bundle subjected to electrolytic surface treatment was washed with water and dried in heated air to obtain a carbon fiber bundle as a raw material.

Step 2: attaching a sizing agent to a carbon fiber bundle

Using (A-1) as the compound (A), an aqueous solution of about 0.2 mass% in which (A-1) was uniformly dissolved was obtained by mixing (A-1) with water. The sizing agent was applied to the surface-treated carbon fiber bundle by an immersion method using this aqueous solution as a sizing agent aqueous solution, and then, as a pre-drying step, heat-treated with a hot roll at a temperature of 120 ℃ for 15 seconds, and then, as a 2 nd drying step, heat-treated in heated air at a temperature of 210 ℃ for 90 seconds, to obtain a carbon fiber bundle coated with the sizing agent. The amount of the sizing agent attached was adjusted to 0.09 parts by mass relative to 100 parts by mass of the total amount of the surface-treated carbon fiber bundle coated with the sizing agent.

The average tearable distance of the carbon fiber bundle at this time was 1000 mm.

Step 3: preparation and evaluation of sample for fiber opening test

The carbon fiber bundle obtained in the above 2 step was used to determine the opening retention and the number of non-opened portions based on the evaluation method of the opening property. As a result, when the non-opened portion was evaluated, the number of the non-opened portions was 1 and the opening retention ratio was 0.94, and it was found that the opening property was very high.

Step 4: preparation and evaluation of IFSS measurement test piece

Using the carbon fiber bundles obtained in the above-described steps and (C-1) as the thermoplastic resin (C), test pieces for IFSS measurement were prepared based on the method for measuring the interfacial shear strength. The hot pressing conditions are 320 ℃ and 2.0 MPa.

Subsequently, IFSS was measured using the obtained IFSS measurement test piece. As a result, IFSS was 43MPa, and it was found that the adhesiveness was sufficiently high. The results are summarized in Table 1.

[ Table 1]

(example 2)

A carbon fiber bundle coated with a sizing agent was obtained and subjected to various evaluations in the same manner as in example 1, except that the amount of sizing agent attached in the 2 nd step was adjusted to 0.07 parts by mass per 100 parts by mass of the total amount of the carbon fiber bundle coated with the sizing agent. As a result, as summarized in table 1, carbon fiber bundles having very high adhesion and fiber opening properties were obtained.

(example 3)

A carbon fiber bundle coated with a sizing agent was obtained in the same manner as in example 1 except that (a-2) was used as the compound (a) in the 2 nd step and the amount of the sizing agent attached was adjusted to 0.08 parts by mass based on 100 parts by mass of the total amount of the carbon fiber bundle coated with the sizing agent, and various evaluations were performed. As a result, as summarized in table 1, carbon fiber bundles having very high adhesion and fiber opening properties were obtained.

(example 4)

A carbon fiber bundle coated with a sizing agent and a test piece for IFSS measurement were obtained and subjected to various evaluations in the same manner as in example 1, except that (C-2) was used as the thermoplastic resin (C) in the 4 th step. As a result, as summarized in table 1, a carbon fiber bundle having very high adhesion and sufficiently high fiber opening property was obtained.

(example 5)

A carbon fiber bundle coated with a sizing agent was obtained in the same manner as in example 2 except that interlacing was applied when obtaining the carbon fiber bundle in the step 1, and various evaluations were performed. As a result, as summarized in table 1, carbon fiber bundles having sufficiently high adhesion and fiber opening properties were obtained.

(example 6)

A carbon fiber bundle coated with a sizing agent was obtained in the same manner as in example 1 except that the drying temperature in the 2 nd drying step was changed to 120 ℃. As a result, carbon fiber bundles having very high adhesion and fiber opening property were obtained as summarized in table 2.

[ Table 2]

(example 7)

A carbon fiber bundle coated with a sizing agent was obtained in the same manner as in example 2 except that the drying temperature in the 2 nd drying step was changed to 25 ℃ in the 2 nd step, and various evaluations were performed. As a result, carbon fiber bundles having very high adhesion and fiber opening property were obtained as summarized in table 2.

(example 8)

In the 2 nd step, (A-1) and (B-1) were mixed with water so that the proportion of the compound (B-1) was 15 parts by mass based on 100 parts by mass (excluding the solvent) of the total amount of the sizing agent, to obtain an aqueous solution of about 0.1% by mass in which the compound was uniformly dissolved. A carbon fiber bundle coated with a sizing agent was obtained and subjected to various evaluations in the same manner as in example 1, except that this aqueous solution was used as a sizing agent aqueous solution and the 2 nd drying temperature was changed to 80 ℃. As a result, carbon fiber bundles having very high adhesion and fiber opening property were obtained as summarized in table 2.

(example 9)

Various evaluations were carried out in the same manner as in example 8 except that the 2 nd drying temperature was changed to 210 ℃ and the amount of sizing agent attached was adjusted to 0.06 parts by mass per 100 parts by mass of the total amount of the carbon fiber bundle coated with the sizing agent in the 2 nd step. As a result, carbon fiber bundles having very high adhesion and fiber opening property were obtained as summarized in table 2.

(example 10)

Various evaluations were carried out in the same manner as in example 8 except that the 2 nd drying temperature was changed to 210 ℃ and the amount of sizing agent attached was adjusted to 0.09 parts by mass per 100 parts by mass of the total amount of the carbon fiber bundles coated with the sizing agent in the 2 nd step. As a result, carbon fiber bundles having very high adhesion and fiber opening property were obtained as summarized in table 2.

(example 11)

Various evaluations were carried out in the same manner as in example 8 except that the 2 nd drying temperature was changed to 260 ℃ and the amount of the sizing agent attached was adjusted to 0.09 parts by mass per 100 parts by mass of the total amount of the carbon fiber bundles coated with the sizing agent in the 2 nd step. As a result, as summarized in table 2, a carbon fiber bundle having very high adhesion and sufficiently high fiber opening property was obtained.

(example 12)

A carbon fiber bundle coated with a sizing agent was obtained in the same manner as in example 1, except that the drying temperature in the 2 nd drying step was changed to 260 ℃. As a result, as summarized in table 2, a carbon fiber bundle having very high adhesion and sufficiently high fiber opening property was obtained.

Comparative example 1

A carbon fiber bundle coated with a sizing agent was obtained and subjected to various evaluations in the same manner as in example 1, except that the amount of sizing agent attached in the 2 nd step was adjusted to 0.12 parts by mass per 100 parts by mass of the total amount of the carbon fiber bundle coated with the sizing agent. As a result, as summarized in table 1, carbon fiber bundles having very high adhesion but low fiber opening property were obtained.

Comparative example 2

A carbon fiber bundle coated with a sizing agent was obtained in the same manner as in example 1 except that (a-3) was used as the compound (a) in the 2 nd step and the amount of the sizing agent attached was adjusted to 0.08 parts by mass based on 100 parts by mass of the total amount of the carbon fiber bundle coated with the sizing agent, and various evaluations were performed. As a result, as summarized in table 1, carbon fiber bundles having very high adhesion but low fiber opening property were obtained.

Comparative example 3

A carbon fiber bundle coated with a sizing agent was obtained and subjected to various evaluations in the same manner as in example 1, except that the amount of sizing agent attached in the 2 nd step was adjusted to 0.02 parts by mass based on 100 parts by mass of the total amount of the carbon fiber bundle coated with the sizing agent. As a result, carbon fiber bundles having low adhesion and very high fiber opening property were obtained as summarized in table 1.

Comparative example 4

A carbon fiber bundle coated with a sizing agent was obtained and subjected to various evaluations in the same manner as in example 5, except that the amount of sizing agent attached in the 2 nd step was adjusted to 0.12 parts by mass per 100 parts by mass of the total amount of the carbon fiber bundle coated with the sizing agent. As a result, as summarized in table 1, carbon fiber bundles having very high adhesion but low fiber opening property were obtained.

Comparative example 5

A carbon fiber bundle coated with a sizing agent was obtained in the same manner as in example 1 except that no sizing agent was attached in the step 2, and various evaluations were performed. As a result, as summarized in Table 1, carbon fiber bundles having very high opening property were obtained, but in the molded article using (B-1) as the component (B), only low interfacial shear strength was exhibited.

[ Table 3]

(example 13)

In the present example, a thermoplastic resin molded body was produced by the following procedure.

First, the carbon fiber bundles coated with the sizing agent obtained in example 2 were aligned to prepare a carbon fiber sheet. Next, 4 sheets of the above-described carbon fiber sheet were inserted between 5 sheets of a thermoplastic resin (C-1) film having a thickness of 30 μm. The laminated film was placed in a hydraulic vacuum molding machine heated to 370 ℃ and preheated under vacuum for 4 minutes. After pressing at 10MPa for 4 minutes, the molded article was cooled at 30 ℃ for 2 minutes and demolded to obtain the intended thermoplastic resin molded article.

The thermoplastic resin composition described above had no voids therein, and it was confirmed that the impregnation property was very high. The results are summarized in Table 3.

Comparative example 7

A thermoplastic resin composition was produced in the same manner as in example 9, except that the sizing agent-coated carbon fiber bundle obtained in comparative example 1 was used. As a result, as summarized in table 3, voids were observed in the thermoplastic resin molded article, and it was confirmed that the impregnation property was low.

(example 14)

The present embodiment includes the following steps 1 to 4.

Step 1: process for producing carbon fiber bundle as raw material

The acrylonitrile copolymer was spun and fired to obtain a carbon fiber bundle having a total number of filaments of 12,000, a total fineness of 800tex, a strand tensile strength of 5.1GPa, and a strand tensile elastic modulus of 240 GPa. Next, the carbon fiber bundle was subjected to electrolytic surface treatment using an aqueous ammonium bicarbonate solution as an electrolyte solution at an electric quantity of 80 coulombs per 1g of the carbon fiber bundle. The carbon fiber bundle subjected to electrolytic surface treatment was then washed with water and dried in heated air to obtain a carbon fiber bundle as a raw material.

Step 2: attaching a sizing agent to a carbon fiber bundle

The compound (A-1) and the compound (B-1) were mixed in the composition shown in Table 4, and water was added to obtain an aqueous solution of about 0.8 mass% in which the compounds (A-1) and (B-1) were uniformly dissolved. The sizing agent is applied to the surface-treated carbon fiber bundle by an immersion method using the aqueous solution as a sizing agent aqueous solution, and then dried in heated air by a hot roll to obtain a carbon fiber bundle coated with the sizing agent. The amount of the sizing agent attached was adjusted to 0.3 parts by mass relative to 100 parts by mass of the total amount of the surface-treated carbon fiber bundle coated with the sizing agent.

Step 3: preparation and evaluation of sample for fiber opening test

The opening width was determined based on the evaluation method of the opening property using the carbon fiber bundle obtained in the above-described step 2. As a result, the opening width was 5.1, and it was found that the opening property was very high.

Step 4: preparation and evaluation of IFSS measurement test piece

Using the carbon fiber bundles obtained in the above-described steps and (C-1) as the thermoplastic resin (C), test pieces for IFSS measurement were prepared based on the method for measuring the interfacial shear strength. The heating condition for hot pressing was 320 ℃.

Subsequently, the IFSS was measured using the obtained IFSS measurement test piece. As a result, IFSS was 43MPa, and it was found that the adhesiveness was sufficiently high. The results are summarized in Table 4.

[ Table 4]

(examples 15 to 20)

A carbon fiber bundle coated with a sizing agent was obtained in the same manner as in example 14, except that the composition of the sizing agent in the step 2 was changed as shown in table 4, and various evaluations were performed. As a result, as summarized in table 4, carbon fiber bundles having sufficiently high adhesion and fiber opening property were obtained.

Comparative examples 8 and 9

A carbon fiber bundle coated with a sizing agent was obtained in the same manner as in example 14, except that the composition of the sizing agent in the step 2 was changed as shown in table 4, and various evaluations were performed. As a result, the fiber opening property was insufficient as summarized in Table 4.

(examples 21 to 24)

A carbon fiber bundle coated with a sizing agent was obtained in the same manner as in example 14, except that the composition of the sizing agent in the step 2 was changed as shown in table 5, and various evaluations were performed. As a result, as summarized in table 5, carbon fiber bundles having sufficiently high adhesion and fiber opening property were obtained.

[ Table 5-1]

[ tables 5-2]

Comparative examples 10 and 11

A carbon fiber bundle coated with a sizing agent was obtained and subjected to various evaluations in the same manner as in example 14, except that the composition of the sizing agent in the step 2 was changed as shown in table 5. As a result, the adhesiveness was insufficient as summarized in Table 5.

Comparative examples 12 to 14

A carbon fiber bundle coated with a sizing agent was obtained in the same manner as in example 14, except that the composition of the sizing agent in the step 2 was changed as shown in table 5, and various evaluations were performed. As a result, the fiber opening property was insufficient as summarized in Table 5.

(examples 25 to 27)

A carbon fiber bundle coated with a sizing agent was obtained and subjected to various evaluations in the same manner as in example 14, except that the amount of the sizing agent attached in the 2 nd step was changed as shown in table 5 with respect to 100 parts by mass of the total amount of the carbon fiber bundle coated with the sizing agent. As a result, as summarized in table 5, carbon fiber bundles having sufficiently high adhesion and fiber opening property were obtained.

(examples 28 to 29)

Various evaluations were carried out in the same manner as in example 14 except that the composition of the sizing agent in the 2 nd step was changed as shown in table 5 and the amount of the sizing agent attached was changed as shown in table 5 with respect to 100 parts by mass of the total amount of the carbon fiber bundle coated with the sizing agent. As a result, as summarized in table 5, carbon fiber bundles having sufficiently high adhesion and fiber opening property were obtained.

(example 30)

A carbon fiber bundle coated with a sizing agent and a test piece for IFSS measurement were obtained and subjected to various evaluations in the same manner as in example 14, except that (C-2) was used as the thermoplastic resin (C) in the 4 th step. As a result, as summarized in table 6, carbon fiber bundles having sufficiently high adhesion and sufficiently high fiber opening property were obtained.

[ Table 6]

Comparative examples 15 and 16

A carbon fiber bundle coated with a sizing agent was obtained and subjected to various evaluations in the same manner as in example 23, except that the components of the sizing agent in the step 2 were changed as shown in table 6. As a result, the adhesiveness and the fiber-opening property were not sufficient as summarized in Table 6.

(example 31)

A carbon fiber bundle coated with a sizing agent and a test piece for IFSS measurement were obtained in the same manner as in example 14 except that (C-3) was used as the thermoplastic resin (C) in the 4 th step and the heating condition for hot pressing was changed to 220 ℃. As a result, as summarized in table 6, carbon fiber bundles having sufficiently high adhesion and sufficiently high fiber opening property were obtained.

Comparative examples 17 and 18

A carbon fiber bundle coated with a sizing agent was obtained and subjected to various evaluations in the same manner as in example 31, except that the components of the sizing agent in the step 2 were changed as shown in table 6. As a result, the adhesiveness and the fiber-opening property were not sufficient as summarized in Table 6.

(example 32)

In the present example, a molded article was produced by the following procedure.

First, the carbon fiber bundles coated with the sizing agent obtained in example 14 were aligned to prepare a carbon fiber sheet. Next, 4 sheets of the above-described carbon fiber sheet were inserted between 5 sheets of a thermoplastic resin (C-1) film having a thickness of 30 μm. The laminated film was placed in a hydraulic vacuum molding machine heated to 370 ℃ and preheated under vacuum for 4 minutes. After pressurizing at 10MPa for 4 minutes, the molded article was cooled at 30 ℃ for 2 minutes and demolded to obtain the intended molded article.

No voids were observed in the molded article, and it was confirmed that the impregnation property was sufficiently high. The results are summarized in Table 7.

[ Table 7]

Comparative example 19

A molded article was produced in the same manner as in example 32, except that the sizing agent-coated carbon fiber bundle obtained in comparative example 13 was used. As a result, as summarized in table 7, voids were observed in the molded article, and it was confirmed that the impregnation property was low.

Description of the reference numerals

1: fiber bundle

2: fixed point A

3: fixed point B

4: fixed point C

5: interlacing point

6: tearable distance

Industrial applicability

According to the present invention, it is possible to provide a sizing agent-coated carbon fiber bundle that exhibits good fiber-opening properties in the fiber-opening step of sizing agent-coated carbon fibers even when exhibiting a high level of adhesion to a thermoplastic resin. The thermoplastic resin composition and the molded article thereof of the present invention are lightweight and excellent in strength, and therefore can be suitably used in many fields such as aircraft members, spacecraft members, automobile members, ship members, civil engineering and construction materials, and sporting goods.

Claims

1. A carbon fiber bundle coated with a sizing agent, which is coated with a sizing agent comprising a compound (A) on a carbon fiber, the compound (A) being a polyalkyleneamine or an aliphatic amide, characterized in that the following (ii) is satisfied:

(ii) a sizing agent-coated carbon fiber bundle in which carbon fibers are coated with a sizing agent in which the total amount of a compound (A) and a compound (B) represented by the following formula (I) and/or (II) is 50 parts by mass or more per 100 parts by mass of the total amount of the sizing agent, the mass WA of the compound (A) and the mass WB of the compound (B) satisfy the formula (III), and the difference between the SP values of the compound (A) and the compound (B) is 0.5 to 4.0 (J/cm)³)^0.5，

R₁-COO-(CH₂CH₂O)_n-CO-R₂The product is shown in formula (I)

R₃-COO-(CH₂CH₂O)_n-H, formula (II)

In the formula, R₁、R₂、R₃A hydrocarbon group having 1 or more carbon atoms, n is 9 to 100,

0.1 < WB/(WA + WB) <0.6 · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · ·.

2. The sizing-agent-coated carbon fiber bundle according to claim 1, wherein the compound (a) is polyalkyleneimine.

3. The sizing-agent-coated carbon fiber bundle according to claim 1 or 2, which is the case satisfying the (ii), and the HLB of the compound (B) is 10 or more.

4. The sizing-agent-coated carbon fiber bundle according to claim 1 or 2, which is the case satisfying the (ii), and n of the compound (B) is 12 or more.

5. The sizing-agent-coated carbon fiber bundle according to claim 1 or 2, which satisfies the condition of (ii), and the melting point of the compound (B) is 20 ℃ or higher.

6. The sizing-agent-coated carbon fiber bundle according to claim 1 or 2, which is the case satisfying the (ii), and the surface free energy of the compound (A) is 45mJ/m²The above.

7. The carbon fiber bundle coated with a sizing agent according to claim 1 or 2, which is the case satisfying the (ii), and the sizing agent contains substantially no compound having an epoxy group.

8. The sizing-agent-coated carbon fiber bundle according to claim 1 or 2, which satisfies the condition of (ii) and has an inter-fiber friction coefficient of 0.30 or less.

9. The sizing-agent-coated carbon fiber bundle according to claim 1 or 2, which is the case satisfying the above (ii), and the attached amount of the sizing agent is 0.01 parts by mass or more and 1.0 parts by mass or less with respect to 100 parts by mass of the sizing-agent-coated carbon fiber.

10. A thermoplastic resin composition comprising the sizing-agent-coated carbon fiber bundle according to any one of claims 1 to 9 and a thermoplastic resin (C).

11. The thermoplastic resin composition according to claim 10, wherein the glass transition temperature of the thermoplastic resin (C) is 200 ℃ or higher.

12. A molded article obtained by using the thermoplastic resin composition according to claim 10 or 11, wherein the molded article is used as a molding material in the form of a prepreg or a UD tape.

13. The method for producing a carbon fiber bundle coated with a sizing agent according to claim 1 or 2, which comprises a step of applying the sizing agent to the carbon fibers with an aqueous solvent.

14. The method for producing a sizing-agent-coated carbon fiber bundle according to claim 13, comprising the steps of:

a pre-drying step of drying the carbon fiber bundle coated with the sizing agent by a contact drying mechanism after the step of coating the sizing agent on the carbon fiber with an aqueous solvent; and a 2 nd drying step of drying the carbon fiber bundle coated with the sizing agent by a contact or non-contact drying mechanism,

the drying temperature in the second drying step 2 is 20 to 250 ℃.

15. A method for producing a molded article, which comprises obtaining a thermoplastic resin composition using the sizing-agent-coated carbon fiber bundle obtained by the method for producing a sizing-agent-coated carbon fiber bundle according to claim 13 or 14 and a thermoplastic resin (B), and which comprises a step of heating the thermoplastic resin composition to 300 ℃ or higher.